Patent Document 1 discloses an in-vehicle type navigation device that conducts a route search utilizing predicted traffic information. The predicted traffic information indicates traffic information on and after the current clock time, which has been generated from past traffic information and current traffic information. This in-vehicle type navigation device downloads the predicted traffic information from a server, and uses the downloaded information for searching a route.
Patent Document 1
Japanese Patent Laid-open Publication No. 2004-280320